Cars have lights. You don't want to be like a car do you? After all, that's why you ride a bike. If you wanted to have lights, you'd drive. Obviously. Ipso facto. (is that what that means?)
Lights reveal your location to bounty hunters. Riding in total darkness helps obfuscate your presence from bounty hunters and avoiding bounty hunters has to be one of your top transportation priorities.
9 out of 10 ophthalmologists endorse lights. And ophthalmologists tend to be jerks, right?
Lights add unnecessary weight and drag to your bicycle. It normally takes me about 45 minutes to ride home, but once I rode home and I had lights on my bike and it took my 46 minutes. That's 60 extra seconds due to the weight and drag caused by lights. 60 seconds I'll never get back. Thanks a lot, lights!
If the Creator/Evolution by Natural Selection wanted us to visible in darkness, he would've made bicyclists bioluminescent. Like the clusterwink snail. Do you really want to offend Zeus/Darwin by imitating the clusterwink snail? Icarus did shit like that and you saw what happened to him. Or read about it. And played a Nintendo game vaguely associated with it. In any case, it was bad news.
People might think that you're a lighthouse or a Christmas tree. Next thing you know, ship pilots will be all confused and/or Santa will show up too early and you'd both ruin Christmas and the global seafaring economy.
Everyone else is wearing night vision goggles so lights are superfluous. Most drivers these days (but not bounty hunters for some reason) already wear night vision goggles, so they can see you perfectly fine. This is especially true of drivers who wear night vision goggles while looking down at their phones while driving.
Most bike lights are malodorous. The same chemicals that provide the power that lights your lights smell really bad. You don't want to have to put a clothespin on your nose, do you?
Bicyclists who have lights on their bikes might break traffic laws. Sure, so might cyclists who don't. But, per the rules of the internet, vague insinuations and anecdotes are good enough to support any assertion, no matter how outlandish.
Lights kind of sound like they could be associated with the Illuminati. You don't need me to tell you why that's bad. Same reason I don't use mason jars- I simply cannot abide being associated with secret societies.
These are just some of the very, very many valid reasons why you should never use lights on your bike at night. While it would be possible to list out many more of the very, very many valid reasons why you should avoid doing this abundantly obvious, safe, legal and self-interestedly helpful thing, I'd prefer not to because those reasons are so extraordinarily obvious and also because the symbol of an idea, as learned from watching many a cartoon, is a lightbulb over one's head and lights, clearly, are the worst.